| CPC E21B 23/04 (2013.01) [E21B 23/001 (2020.05)] | 17 Claims |

|
13. A method for moving a wellbore tractor through a wellbore, the method comprising:
opening a first valve disposed on a hydraulic line between a first pair of drives and a second pair of drives of the wellbore tractor, the first pair of drives in fluid communication with a first section of the hydraulic line, the second pair of drives in fluid communication with a second section of the hydraulic line;
adding, by a hydraulic control unit, hydraulic fluid to the hydraulic line such that the first pair of drives and the second pair of drives are in an extended configuration;
closing the first valve;
removing, by the hydraulic control unit, the hydraulic fluid from the hydraulic line such that the first pair of drives transitions to a retracted configuration and the second pair of drives remains in the extended configuration;
opening the first valve;
opening a second valve disposed on the hydraulic line between the second pair of drives and a third pair of drives, the third pair of drives in fluid communication with a third section of the hydraulic line;
adding, by the hydraulic control unit, the hydraulic fluid to the hydraulic line such that the first pair of drives, the second pair of drives, and the third pair of drives transition to the extended configuration;
closing the first valve; and
removing, by the hydraulic control unit, the hydraulic fluid from the hydraulic line such that the first pair of drives transitions to a retracted configuration and the second pair of drives and the third pair of drives remain in the extended configuration.
|